A primary function of the Mouse Core is to breed, maintain and genotype mice used within the PPG. Dr. Hedrick has extensive experience in the breeding of transgenic and knockout animals and in the maintenance of mouse colonies. The Mouse Core will maintain and genotype all mouse colonies that are used by more than one project. The Core will be responsible for all purchase of commercially available mice needed (such as study controls) for all projects. A secondary function of the Core is to perform bone marrow transplantations in mice. In this case, marrow will be extracted by the Core, and injected into irradiated recipients. The irradiation will be performed by each Project; however after irradiation, marrow injections, mouse housing, and mouse care will be performed by Core personnel. Once the mice have recovered from irradiation, the mice will be provided to each Project for experimentation. In order to keep the numbers and use of mice as limited as is possible, there will be considerable sharing of mouse tissues among the four projects. For example, mice used for obtaining lung endothelial cells can also be used to obtain splenocytes. Other tissues from the mice will be shared among the Projects as needed for immunostaining and microarray analysis.